Gear train for timepiece with a stepping motor

Abstract

A stepping motor driven by a time-based electrical driving signal periodically rotates an overhung gear train directly driving the hour and minute hands mounted on a main arbor. The arbor is rotatably mounted in two spaced journals in a single tapered bearing hole in the frame. An intermediate arbor is similarly journaled. The gear train is assembled from only one side of the timepiece. The main arbor, center gear assembly, hands and dial are all added as a subassembly.

What is claimed is: 
     
       1. An electronic stepping motor timepiece comprising: means generating time-based electrical driving signals,   a stepping motor having a rotor and pinion adapted to periodically rotate in response to said signals,   a frame carrying said stepping motor and having at least one bore defining spaced larger and smaller diameter journal bearings, within said bore,   at least one arbor disposed in said bore having a journal portion with spaced larger and smaller diameter journals, and an overhung portion extending from the frame,   a center wheel attached to said overhung arbor portion and a bushing rotatably disposed on the arbor having an hour wheel attached thereto,   an intermediate gear and pinion assembly rotatably mounted on the frame and driving the center wheel and hour wheel,   said stepping motor pinion directly driving said gear and pinion assembly.   
     
     
       2. An electronic stepping motor timepiece comprising: means generating time-based electrical driving signals,   a stepping motor having a rotor and pinion adapted to periodically rotate in response to said signals,   a frame carrying said stepping motor and having first and second spaced bores, said bores defining journal bearings,   a first overhung arbor disposed in the first bore having a center wheel thereon,   a second overhung arbor disposed in the second bore having a minute wheel fixed thereon driving the center wheel and also having a minute pinion fixed thereon,   a bushing rotatably journaled on the first arbor having thereon an hour wheel driven by said minute pinion,   a separate intermediate wheel disposed on and affixed to the second arbor and driven directly by said stepping motor pinion.   
     
     
       3. The combination according to claim 2 wherein each of said bores defines spaced larger and smaller diameter journal bearings, and wherein said arbors each include a journal portion with spaced larger and smaller diameter journals adapted to rotate in said spaced larger and smaller diameter journal bearings. 
     
     
       4. The combination according to claim 3 wherein said bores comprise a tapered hole connecting said spaced bearings. 
     
     
       5. The combination according to claim 4 wherein said stepping motor comprises a permanently magnetized rotor disposed between two stator members having core pieces cooperating with an electric coil.